OPERATIVE VAGINAL DELIVERY

VACUUM EXTRACTION

Operative Vaginal Delivery Rates.

Delivery with a vacuum cup

Obstetricians should
be confident and competent in the use of forceps and vacuum extractor
for both rotational and non-rotational operative vaginal deliveries. The
anatomy of the birth canal and the fetal head must be understood as a
prerequisite to becoming skilled in the safe use of the forceps or
vacuum extractor. The RCOG
recommends
that obstetricians achieve experience in spontaneous vaginal delivery
prior to commencing training in operative vaginal delivery. The goal of
operative vaginal delivery is to mimic spontaneous vaginal birth,
thereby expediting delivery with a minimum of maternal or neonatal
morbidity.

There has been an
increasing awareness of the potential for morbidity for both the mother
and the baby. The risk of traumatic delivery in relation to forceps,
particularly rotational procedures, has been long established,7901
although with careful practice overall rates of morbidity are low.8701

In 1998, the US Food
and Drug Administration (FDA) issued a warning about the potential
dangers of delivery with the vacuum extractor.
FDA
This followed
several reports of infant fatality secondary to intracranial
haemorrhage. In addition, there has been a growing awareness of the
short- and long-term morbidity of pelvic floor injury following
operative vaginal delivery.0101,0102,0301,0401,0501
It is not surprising, therefore, that there has been an increase in
litigation relating to obstetric delivery. Caesarean section in the
second stage of labour, however, also carries significant morbidity and
implications for future births. If we are to offer women the option of a
safe operative vaginal delivery, we need to improve our approach to
clinical care. The goal should be to minimise the risk of morbidity and,
where morbidity occurs, to minimise the likelihood of litigation,
without limiting maternal choice.

Reducing operative vaginal
delivery rates.

As
As operative
vaginal delivery can be associated with maternal and neonatal morbidity,
strategies that reduce the risk of operative vaginal delivery should be
used.

Continuous support
for women during childbirth can reduce the incidence of operative
vaginal delivery, particularly when the carer was not a member of staff.0302
Use of any
upright or lateral position, compared with supine or lithotomy positions
is associated with a reduction in assisted deliveries.0402
Epidural analgesia appears to be effective
in reducing pain during labour. However, women who use this form of pain
relief are at increased risk of having an instrumental delivery.
Epidural analgesia had no statistically significant impact on the risk
of caesarean section, maternal satisfaction with pain relief and
long-term backache and does not appear to have an immediate effect on
neonatal status as determined by Apgar scores.0502

Using a partogram leads to fewer operative births
and less use of oxytocin.0503
An oxytocin infusion may reduce the high rate of operative delivery in
primigravidae associated with epidural analgesia provided that the fetal
occiput is in an anterior position at the onset of the second stage of
labour8901
Extreme caution should be taken before using oxytocin for the second
stage in multiparous women. Each woman should be assessed individually
for the management of the second stage.

In the study by
Fitzpatrick et al,0202
rates of
instrumental delivery were similar following immediate and delayed
pushing, in association with epidural analgesia.
0303
The
RCOG, however, sites a recent meta-analysis demonstrated that
primiparous women with epidurals were likely to have fewer rotational or
mid-cavity operative interventions when pushing was delayed for 1?2
hours or until they had a strong urge to push.
Upright positions in the second stage with
epidurals were associated with a non-significant reduction in the risk
of both instrumental delivery (relative risk (RR) = 0.77, 95% confidence
interval (CI) = 0.46-1.28) and caesarean section (RR = 0.57, 95% CI =
0.28-1.16).0504

There
is no difference between the rates of operative vaginal delivery for
combined spinal-epidural and epidural techniques.0304

Classification for operative vaginal delivery.

Classification

Outlet

Fetal scalp visible without separating
the labia

Fetal skull has reached the pelvic
floor

Sagittal suture is in the antero-posterior
diameter or right or left occiput anterior or posterior position

(rotation does not exceed 45 degrees)

Fetal head is at or on the perineum

Low

Leading point of the skull (not caput)
is at station plus 2 cm or more and not on the pelvic floor

There are 2 subdivisions:

(a) rotation of 45 degrees or less

(b) rotation more than 45 degrees

Mid

Fetal head is
1/5 palpable per abdomen

Leading point of the skull is above station plus 2 cm but not
above the ischial spines

Two subdivisions (a) rotation of 45 degrees or less

(b) rotation more than 45 degrees

High

Not included in classification

Table 1
Classification of Vaginal Operative Delivery

Indications for operative vaginal delivery.

Operators should be aware that no indication is absolute and should be
able to distinguish standard from special indications.

Operative intervention is used to shorten the second stage of labour. It
may be indicated for conditions of the fetus or of the mother (Table 2).

The question of when to intervene should
involve balancing the risks and benefits of continuing
pushing as against operative delivery.

Nulliparous women: lack of continuing progress for three
hours (total of active and passive second stage labour)
with regional anaesthesia, or two hours without regional
anaesthesia

In a retrospective cohort
study of 15,759 nulliparous, term, cephalic, singleton
births at the University of California,0403
San Francisco, between
1976 and 2001, the second stage of labor was divided into
1-hour intervals. Increasing rates of caesarean delivery,
operative vaginal delivery, and perineal trauma were
associated with the second stage beyond the first hour. In
multivariate analysis, the >4-hour interval group had higher
rates of cesarean delivery, operative vaginal deliveries,
3rd- or 4th-degree perineal lacerations , and
chorioamnionitis. There were no differences in neonatal
acid-base status associated with length of second stage. It
was concluded that although the length of the second stage
of labour was not associated with poor neonatal outcome, a
prolonged second stage is associated with increased maternal
morbidity and operative delivery rates.

Multiparous women: lack of continuing progress for two hours
(total of active and passive second stage labour) with
regional anaesthesia, or one hour without regional
anaesthesia

Maternal
fatigue/exhaustion

Table 2 Indications for operative delivery.

There is no evidence
that elective operative delivery for inadvertent dural puncture is of
benefit, unless the woman has a headache that worsens with pushing.9301

Contraindications to operative vaginal delivery.

Fetal bleeding disorders
(e.g. alloimmune thrombocytopenia) or a predisposition to fracture (e.g.
osteogenesis imperfecta)
are relative contraindications to operative vaginal delivery. However,
there may be considerable fetal risk if the head has to be delivered
abdominally from deep in the pelvis.

In a postal survey of members and fellows of The
Royal College of Obstetricians and gynaecologists,0601
21% thought elective caesarean section is indicated in all fetuses known
to be at risk of being affected by
haemophilia.
Eighty-four percent considered vacuum extraction unsafe in these cases,
but 76% would consider the use of low forceps.

The vacuum extractor is contraindicated with a
face presentation.
It has been suggested that it should not be used at gestations of less
than 36 weeks because of the risk of cephalhaematoma and intracranial
haemorrhage.

In a retrospective, observational study9501
covered 61 infants delivered vaginally with vacuum extraction versus 122
matched controls delivered spontaneously. All infants were at < 37 weeks
of gestation, with birth weights ranging from 1,500 to 2,499 g. Main
neonatal outcomes studied were Apgar scores, umbilical artery blood pH
and base excess, intraventricular haemorrhage, admission to the neonatal
intensive care unit and length of hospital stay. There was a decreased
need for episiotomies in the vacuum-assisted deliveries versus the
controls (41% versus 57%). Neonatal morbidity was not significantly
different in infants with vacuum-assisted deliveries. Vacuum extraction
does not seem to increase neonatal morbidity in preterm infants with
birth weights of 1,500-2,499 g.

At present, the
RCOG recommends avoiding the use of vacuum
below 34 weeks
because of the susceptibility of the preterm infant to cephalohaematoma,
intracranial haemorrhage and neonatal jaundice. There is insufficient
evidence to establish the safety of the vacuum at gestations between 34
and 36 weeks.

The risk of vertical
transmission of
hepatitis C
virus
appears to be related to the level of viraemia in the pregnant mother
and not to the route of delivery. However, it is sensible to avoid
difficult operative delivery where there is an increased chance of fetal
abrasion or scalp trauma, as it is to avoid fetal scalp clips or blood
sampling during labour.

Forceps and vacuum
extractor deliveries before full dilatation of the cervix are
contraindicated. There are a few exceptions which include a prolapsed
cord at 9 cm in a multiparous woman or a second twin. Forceps are
indicated for the aftercoming head of the breech and in situations where
maternal effort is impossible or contraindicated.

Pre-requisites for operative vaginal delivery.

Full
abdominal and vaginal examination

Head
is ≤ 1/5 palpable per abdomen

Vertex
presentation

Cervix
is fully dilated and the membranes ruptured

Exact position of the head can be determined so proper placement
of the instrument can be achieved

Pelvis is deemed adequate

Mother

>Informed
consent must be obtained and clear explanation given

>Appropriate
analgesia is in place, for mid-cavity rotational deliveries this
will usually be a regional block

>A pudendal
block may be appropriate, particularly in the context of urgent
delivery

>Maternal
bladder has been emptied recently

>Indwelling
catheter should be removed or balloon deflated

>Aseptic
techniques

Staff

>Operator must
have the knowledge, experience and skills necessary to use the
instruments

The
goal of operative vaginal delivery is to mimic spontaneous vaginal
birth, thereby expediting delivery with a minimum of maternal or
neonatal morbidity. The complexity of the delivery is related to the
type of delivery, as classified in Table 1. Mid-cavity and rotational
deliveries, independent of the type of instrument used, demand a high
level of clinical and technical skill and the operator must have
received adequate training.0503

Inadequate training may be a key contributor to adverse outcomes and
training is central to patient safety initiatives.0305
Neonatal
trauma is associated with initial unsuccessful attempts at operative
vaginal delivery by inexperienced operators.0404Formal education
and training of medical staff did not influence the success rate of
instrumental delivery but was associated with improved safety for both
mother and baby.

Place for operative vaginal delivery.

Operative vaginal births that have a higher rate
of failure should be considered a trial and conducted in a place where
immediate recourse to caesarean section can be undertaken.

Higher rates of failure are associated with:

maternal body mass index greater than 30

estimated fetal weight greater than 4000 g or
clinically big baby

occipito-posterior position

mid-cavity delivery or when 1/5 head palpable
per abdomen.

At mid-cavity, the biparietal diameter is still
above the level of the ischial spines. Failure rates are higher at this
station. High maternal body mass index (greater than 30), neonatal birth
weight greater than 4000 g, and occipito-posterior positions are also
indicators of increased failure.0103
Operative deliveries that are anticipated
to have a higher rate of failure, therefore, should be considered a
trial of labour and conducted in a place where immediate recourse to
caesarean can be undertaken. Failed instrumental delivery performed as a
trial of forceps and/or vacuum in a setting where a cesarean section can
follow promptly is not associated with increased morbidity of either
mother or baby.9701

There
is insufficient evidence to assess the benefits and risks of conducting
operative vaginal birth in midwifery led units.

Which instrument for operative vaginal delivery?

The
operator should choose the instrument most appropriate to the clinical
circumstances and their level of skill. Forceps and vacuum extraction
are associated with different benefits and risks. The options available
for rotational delivery include Kielland forceps, manual rotation
followed by direct traction forceps or rotational vacuum extraction.
Rotational deliveries should be performed by experienced operators, the
choice depending upon the expertise of the individual operator.

Metal cups appear to be
more suitable for 'occipito-posterior', transverse and difficult
'occipito-anterior' position deliveries. The soft cups seem to be
appropriate for straightforward deliveries.0002
Soft cups are significantly more likely to fail to achieve vaginal
delivery (odds ratio 1.65, 95% confidence interval 1.19 to 2.29).
However, they were associated with less scalp injury. The soft cups seem
to be appropriate for straightforward deliveries.

In the review by
Johanson and Menon,0003
ten trials were included. Use of the vacuum extractor for assisted
vaginal delivery when compared to forceps delivery was associated with:

there were more
deliveries with vacuum extraction (odds ratio 1.69, 95% confidence
interval 1.31 to 2.19).

fewer caesarean
sections were carried out in the vacuum extractor group.

the vacuum
extractor was associated with an increase in neonatal
cephalhaematomata and retinal haemorrhages.

serious neonatal
injury was uncommon with either instrument.

It was concluded that
the use of the vacuum extractor rather than forceps for assisted
delivery appears to reduce maternal morbidity. The reduction in
cephalhaematoma and retinal haemorrhages seen with forceps may be a
compensatory benefit.

There is no evidence to
suggest that at five years after delivery use of the ventouse or forceps
has specific maternal or child benefits or side effects.9901

The data available from
the published controlled trials cannot be analysed separately to compare
vacuum and forceps in their use for rotational deliveries.

Abandoning
operative vaginal delivery.

Operative vaginal
delivery should be abandoned where there is no evidence of progressive
descent with each pull or where delivery is not imminent following three
pulls of a correctly applied instrument by an experienced operator.
Adverse outcomes, including unsuccessful forceps or vacuum delivery,
should trigger an incident report as part of effective risk management
processes.

The use of multiple
instruments was associated with increased neonatal trauma (adjusted OR
3.1, 95% CI 1.5, 6.8; adjusted OR 4.4, 95% CI 1.3, 14.4, for completed
and failed deliveries, respectively). Excessive pulls and multiple
instrument use were associated with an initial attempt at vaginal
delivery by an inexperienced operator, 25/48 (52%) and 34/75 (45%).0305

The bulk of malpractice litigation
results from failure to abandon the procedure at the appropriate time,
particularly the failure to eschew prolonged, repeated or excessive
traction efforts in the presence of poor progress. Adverse events,
including unsuccessful forceps or vacuum extraction, birth trauma, term
baby admitted to the neonatal unit, low Apgar scores (Apgar less than 7
at 5 minutes) and cord arterial pH less than 7.1 should trigger an
incident report and review, if necessary, as part of effective risk
management processes.

Sequential
use of instruments for operative vaginal delivery.

The use of sequential
instruments is associated with an increased risk of trauma to the
infant. However, the operator must balance the risks of a
caesarean section following failed vacuum extraction with the risks of
forceps delivery following failed vacuum extraction.

The use of outlet
forceps following failed vacuum extraction may be judicious in avoiding
a potentially complex caesarean section.
Caesarean section in the second stage of labour is associated with an
increased risk of major obstetric haemorrhage, prolonged hospital stay
and admission of the baby to SCBU compared to completed instrumental
delivery.0103
Sequential use of instrumental delivery
carries a significantly higher neonatal morbidity than when a single
instrument is used.0306

Ezenagu et al9901
found that the prudent use of sequential instruments at operative
vaginal delivery did not engender higher rates of maternal or neonatal
morbidity whereas others concluded that sequential use of vacuum and
forceps is associated with increased risk of both neonatal and maternal
injury.0104

The sequential use of
instruments should not be attempted by an inexperienced operator without
direct supervision and should be avoided wherever possible.

Episiotomy
and operative vaginal delivery.

If obstetric indications necessitate forceps delivery, performance of an
episiotomy decreases the risk of perineal tears of all degrees. When
analyzing the type of episiotomy, mediolateral episiotomy seems to be
more protective against perineal trauma in women undergoing forceps
delivery.0307

The
role of routine episiotomy for operative vaginal delivery is poorly
evaluated and warrants further research.

Post
Delivery Management.

Mid-cavity delivery, prolonged labour and immobility are risk factors
for thromboembolism. Women should be reassessed after delivery for risk
factors for venous thromboembolism and considered forthromboprophylaxis
if necessary.

Paracetamol and
ibuprofen were rated similarly asanalgesicsforperineal pain.
Ibuprofen may be the preferred choice because it is less
expensive and requires less nursing time to dispense. Further studies
need to address improved analgesia for women with forceps-assisted
deliveries.0105

Care is required to ensure appropriatebladder function.
Clinically
overt postpartum urinary retention complicates approximately 1 in 200
vaginal deliveries, with most resolving before hospital dismissal.
Factors that are independently associated with its occurrence include
instrument-assisted delivery and regional analgesia.0203
Persistent postpartum urinary retention in contemporary obstetric
practice is rare but may be associated with long-term bladder
dysfunction. Early diagnosis and intervention are required to prevent
irreversible bladder damage.0106
The timing and
volume ofthe
first void urine should be monitored. All women undergoing an operative
vaginal delivery should have a fluid balance chart, for at least 24
hours, to detect postpartum urinary retention. A post-void residual
should be measured if retention is suspected.

Women who have had
spinal anaesthesia or epidural anaesthesia that has been topped up for a
trial of labour may be at increased risk of retention and should be
offered an indwelling catheter, to be kept in place for at least 12
hours following delivery to prevent asymptomatic bladder overfilling.

Women should be
offered physiotherapy-directed strategies to prevent urinary
incontinence.
Following physiotherapy intervention, at three months after delivery,
the prevalence of incontinence in the intervention group was 31.0% (108
women) and in the usual care group 38.4% (125 women); difference 7.4%.
At follow up significantly fewer women with incontinence were classified
as severe in the intervention group (10.1%) v (17.0%).0204

Reducing
fear of subsequent childbirth.

Operative vaginal delivery can be associated with fear of subsequent
childbirth and in a severe form may manifest as a post-traumatic
stress type syndrome which has been referred to as ?tokophobia?.

Three
per cent of women had
post-traumatic stress at least once within 1-11 months postpartum.0602

Operative intervention in first childbirth carries
significant psychological risks rendering those who experience these
procedures vulnerable to a grief reaction or to posttraumatic
distress and depression.9702

Women consider postnatal debriefing and medical review important
deficiencies in current care. Those who experienced operative
delivery in the second stage of labour would welcome the opportunity
to have a later review of their intrapartum care, physical recovery,
and management of future pregnancies.0308

Posttraumatic stress disorder after childbirth
is a poorly recognized phenomenon. Women who experienced both a high
level of obstetric intervention and dissatisfaction with their
intrapartum care are more likely to develop trauma symptoms than
women who receive a high level of obstetric intervention or women
who perceive their care to be inadequate. These findings should
prompt a serious review of intrusive obstetric intervention during
labor and delivery, and the care provided to birthing women.0004

Following instrumental vaginal delivery, fear
of childbirth was a reported by 51% as a reason for avoiding a
further pregnancy.0405This is a surprising thought provoking
observation, particularly as we believe that we are using adequate
analgesia.

The support, counseling, understanding, and
explanation given to women by midwives in the postnatal period
provides benefits to psychological well-being. Maternity units have
a responsibility to develop a service that offers all women the
option of attending a session to discuss their labor.9801
In another study, however, midwife led debriefing after operative
birth proved to be ineffective in reducing maternal morbidity at six
months postpartum. The possibility that debriefing contributed to
emotional health problems for some women could not be excluded.0005

Future
deliveries.

Sources:

Those delivered spontaneously and by vacuum,
low forceps and mid-forceps in their first pregnancy had a 96%, 91%,
88% and 82% chance, respectively, of spontaneous delivery in their
next pregnancy.0006